AbstractAs anionic five‐coordinate silicon species (five‐coordinate silicates) exhibit high reactivity and unique fluxional behavior, their structure and property have received substantial attention. We report herein synthesis, structure, and fluxional behavior of alkoxy(tetraaryl)silicates having the 9,10‐disilatriptycene skeleton (6− and 7−). The molecular structure of the cryptate salt [Li(crypt‐222)]+7− shows that the five‐coordinate silicon adopts a distorted trigonal bipyramidal structure with oxygen atom occupying an equatorial position. In the 1H and 13C{1H} NMR spectra of [Li(crypt‐222)]+7−, a set of signals due to o‐phenylene blades in 7− was observed at room temperature, which indicates fluxional behavior of 7− on the NMR timescale. Computational study suggests that the observed process proceeds via a 120° rotation of bidentate ligand around the Si‐Si axis that consists of two sequential Berry pseudorotations.